Automapper map from one object to nested objects

Question

What is the best way to map inner objects with Automapper 2.0

Use the solution in this question (Automapper 1.0)
Create a Custom Value Resolvers

?

public class DTOObject
{
    // MainObject
    public int Id { get; set; }
    public string Name { get; set; }

    // SubObject (TopObject)
    public string TopText { get; set; }
    public string TopFont { get; set; }

    // SubObject (BottomObject)
    public string BottomText { get; set; }
    public string BottomFont { get; set; }
}

public class MainObject
{
    public int Id { get; set; }
    public string Name { get; set; }

    public SubObject TopObject { get; set; }
    public SubObject BottomObject { get; set; }
}

public class SubObject
{
    public string SubPropText { get; set; }
    public string SubPropFont { get; set; }
}

Custom Value Resolvers

    public class CustomResolver : ValueResolver<DTOObject, SubObject>
    {
        protected override SubObject ResolveCore(DTOObject source)
        {
            return Mapper.Map<DTOObject, SubObject>(source);
        }
    }

Which direction are you trying to go, DTOObject to MainObject or MainObject to DTOObject? — sean woodward
– sean woodward, Commented Feb 2, 2012 at 19:58
Probably best to use Mapper.CreateMap<DTOObject, MainObject>().ForMember(d => d.TopObject, mc => mc.MapFrom(s => new SubObject(){ SubPropText = s.TopText, SubPropFont = s.TopFont } )); — sean woodward
– sean woodward, Commented Feb 2, 2012 at 22:43
Also note, in your CustomResolver you shouldn't call Mapper.Map() you should create the SubObject using the properties from the source and return that. — sean woodward
– sean woodward, Commented Feb 2, 2012 at 22:44

Leo Rapaic · Accepted Answer · 2023-09-14 08:06:41Z

14

For me it was possible to use just MapFrom (without ResolveUsing what gives you a chance to use this mapping with IQueryable extensions). So you will get the following in the Automapper configuration:

Mapper.CreateMap<DTOObject, SubObject>()
    .ForMember(dest => dest.SubPropText, opt => opt.MapFrom(x => x.BottomText))
    .ForMember(dest => dest.SubPropFont, opt => opt.MapFrom(x => x.BottomFont));

Mapper.CreateMap<DTOObject, MainObject>()
    .ForMember(dest => dest.TopPart, opt => opt.MapFrom(x => x))
    .ForMember(dest => dest.BottomPart, opt => opt.MapFrom(x => x));

edited Sep 14, 2023 at 8:06

Leo Rapaic

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answered Nov 9, 2015 at 1:28

Yaroslav Ryapolov

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Comments

Leo Rapaic · Accepted Answer · 2023-09-15 23:25:51Z

I ended up creating my own value resolvers for any SubObjects of MainObject that come from DTOObject.

public class PartResolver<T> : ValueResolver<DTOObject, T>
{
    protected override T ResolveCore(DTOObject source)
    {
        return Mapper.Map<T>(source);
    }
}

Then in my Automapper config I create a map from the DTOObject to SubObject and use the ValueResolver to map that object into the MainObject

Mapper.CreateMap<DTOObject, SubObject>();

Mapper.CreateMap<DTOObject, MainObject>()
    .ForMember(dest => dest.TopPart, opt => opt.ResolveUsing<PartResolver<SubObject>>())
    .ForMember(dest => dest.BottomPart, opt => opt.ResolveUsing<PartResolver<SubObject>>());

Shivkumar Haldikar · Accepted Answer · 2021-02-02 16:53:17Z

1

ResolveUsing is not available with latest version of AutoMapper. So only option left is to use MapFrom. (use @ZedRoth solution).

answered Feb 2, 2021 at 16:53

Shivkumar Haldikar

711 silver badge1 bronze badge

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